Pediatric Cerebral Palsy Gait Patterns: 2D Sagittal Stick Diagram

Gait Pattern

Pattern severity 40%

Cadence 90 steps/min

Live Readouts

Knee flexion, midstance

5.0°

Hip adduction, stance

0.0°

Ankle @ heel strike

0.0°

Gait cycle phase

Crouch index (0 = upright, 1 = severe crouch)

0.10

How it works

This is the 2D companion to the 3D pediatric gait simulator, computed independently rather than a flattened render of the 3D scene. It keeps the exact same joint-angle physics — key-framed hip/knee/ankle flexion curves θ(t) over the gait cycle t ∈ [0,1), cosine-interpolated between clinical-trace control points — but draws it the way a real gait-lab report does: as a 2D sagittal-plane stick diagram, both legs overlapping in the same side-view plane instead of splayed apart in 3D, plus a live joint-angle-vs-cycle chart with no 3D equivalent.

θ(t) = lerp_cos( θᵢ, θᵢ₊₁, (t − tᵢ)/(tᵢ₊₁ − tᵢ) )   for tᵢ ≤ t < tᵢ₊₁
lerp_cos(a,b,u) = a + (b−a)·(1 − cos(πu))/2

The left leg uses phase t, the right leg uses phase (t + 0.5) mod 1 — a 50%-offset walking gait. Three cerebral-palsy patterns are parametrized deviations from the typical curve, scaled by severity s ∈ [0,1]:

Crouch:     knee(t) += 35°·s   (persistent stance flexion — never fully extends)
            hip(t)  += 18°·s ,  ankle(t) += 12°·s (excess dorsiflexion)
Scissoring: hip_adduction(t) = 22°·s·sin²(πt)   (thighs cross toward midline in stance)
Toe-walk:   ankle(t) −= 30°·s  for t < 0.5   (equinus / early plantarflexion, no heel strike)

Knee flexion at midstance and hip adduction at mid-stance are the two angles orthopedists watch most closely on a real gait-lab printout. The chart under the walker plots the full hip/knee/ankle curves for the current pattern and severity across one gait cycle, with a moving cursor marking exactly where the animated figure is right now — a diagnostic view a 3D render can't show at a glance. The crouch index is a simple 0–1 composite of knee + hip flexion deviation from typical, a rough severity proxy clinicians use before a full instrumented gait analysis.

Drag the walking view to pan, scroll to zoom — the figure keeps walking forward across the ground plane rather than in place.
Forward stride length shortens automatically with severity for crouch and toe-walking, matching the shorter, more cautious steps seen clinically in those patterns.

This is a simplified educational model, not patient-specific clinical data — real gait analysis uses motion capture and force plates to measure these curves directly.

Drag to pan · Scroll to zoom

Right leg Left leg